The present invention relates to a thumb pad for a thumb hole in a bowling ball.
U.S. Pat. No. 4,530,502 to Yamane discloses a bowling ball thumb hole insert. The insert includes a semi-cylindrical end piece which fits within a thumb hole of a bowling ball. A non-metallic, plastic, flexible plate is attached to the end piece and extends upward therefrom. The end piece is placed at the bottom of the thumb hole. The flexible plate is curved such that it forms an interspace between the wall of the thumb hole and the inner surface of the plate. The outer surface of the plate, which is convexly curved, rests against the back of the bowler's thumb. Yamane also discloses a device which is cylindrically shaped. The cylindrical insert has two longitudinally extending slots therein. These slots define a semi-cylindrical shape. The semi-cylindrical portion of the insert has a cushioning pad disposed between the outside of the insert near the wall of the thumb hole and the hard inner wall defining the semi-cylindrical insert portion. The bowler's thumb rests against the hard inside surface of the insert. U.S. Pat. No. 4,569,520 to Yamane discloses a similar thumb insert.
U.S. Pat. No. 4,416,452 to Heimbigner discloses a bowling ball finger grip insert. The insert is tubular in shape and consists of an inner resilient sleeve disposed at the bottom of the insert (at a position near the bottom of the finger hole of the bowling ball) and an outer hard sleeve. The distal end of the bowlers finger, particularly the finger pad, is placed adjacent or next to the resilient sleeve. The distal joint of the finger is disposed above the resilient sleeve and next to the hard outer sleeve.
U.S. Pat. No. 4,561,654 to Haza discloses a device for adjusting the diameter for bowling balls. U.S. Pat. No. 4,890,836 to Goldie discloses a bowling ball insert which is made of a cylindrical tube of resilient material. The insert is cylindrical in shape and is molded of a silicone having a Shore hardness of 50. A ballast is provided at the distal end or the bottom of the cylindrical insert. By adjusting the weight of the ballast, the balance of the bowling ball is adjusted.
U.S. Pat. No. 4,432,546 to Allen, Jr. discloses a finger insert for bowling balls. The insert is generally cylindrical in shape and includes a series of corrugations or ribs which extend horizontally about the interior surface of the cylindrical insert. The ribs cushion the pads of the bowler's fingers during use. The insert is thick near the top surface of the finger hole and gradually decreases in thickness near the bottom of the finger hole. The pads of the bowler's finger tips contact the ribs of the insert, not the back side of the fingers.
None of these prior art devices provided a cushion for the backside of a bowler's thumb intermediate the medial knuckle of the thumb and the proximal thumb joint which attaches the thumb to the bowler's hand.